The Australian test that was performed showed some interesting promise to indicate that there is a physical cause to gender identity dysphoria. I hope that the study is expanded. However abnormal levels of the aromatase enzyme (it's not a gene there is a gene responsible for it's biosynthetic behavior) cannot be a definitive indicator of GID.
Higher levels of aromatase is also linked to breast cancer in women and Gynocomastia in male body builders.
But the bottom line is that even if there is a true, real, genetic switch or event that could be found that absolutely, one hundred percent of the time PROVE that a person was transsexual, it would have little bearing on the outcome. We would still be caterpillars seeking to become butterflys. I doubt very much that there would be some "cure" anytime soon that would release us from the prison we find ourselves in.
And even if there were, would you take it? This "red pill/blue pill" type question has been asked repeatedly here and in other places. Oddly, most people feel that if their GID were cured and they became happy about being their birth gender that they would feel that it was akin to dying. That we would be changing to allow society the comfort of not having to deal with icky trans people.
For me, sorry, but no. Society has to learn to deal with me and my brothers and sisters, not the other way around.
-Sandy